The present invention relates to substrate coatings and treated ink jet printable textile fabric substrates which are intended to receive images when printed by ink jet printing devices. In particular, the present invention relates to methods of construction or fabrication of an ink jet printable textile substrate which facilitates the use of such substrate in commonly available ink jet or laser printing devices, such as wide or narrow format ink jet and laser printers.
Ink jet printing is a non-impact and non-contact printing method in which an electronic signal controls and directs droplets or a stream of ink that can be deposited on a wide variety of substrates. Current ink jet printing technology involves forcing the ink drops through small nozzles by piezoelectric pressure, thermal ejection, or oscillation, and onto the surface of a material/media. Ink jet printing is extremely versatile in terms of the variety of substrates that can be treated, as well as the print quality and the speed of operation that can be achieved. In addition, ink jet printing is digitally controllable. For these reasons, ink jet methodology has been widely adopted for industrial marking and labeling. In addition, ink jet printing methodology has also found widespread use in architectural and engineering design applications, medical imaging, office printing (of both text and graphics), geographical imaging systems (e.g., for seismic data analysis and mapping), signage, in display graphics (e.g., photographic reproduction, business and courtroom graphics, graphic arts), and the like. Finally, ink jet printing has now also been used to create an image on a variety of textile substrates.
The use of ink-jet printing to create an image on textile fabrics has allowed for the rapid visualization of an aesthetic design on fabric without the use of expensive and often wasteful screen printing techniques. Such ink-jet printing methodology allows a designer, design house, or production facility to visualize a finished design in significantly less time than is usually necessary to burn a screen image of the design by typical screen printing methodology.
Both dyes and pigments have been used as colorants for such ink jet ink formulations. However, such materials do not always bind well to substrates to which the ink is applied. For example, dyes may dissolve upon a substrate""s contact with water. Thus images applied employing ink jet methodology may tend to run or smear upon repeated contact, or may be actually removed from the printed surface if exposed to substantial quantities of aqueous media (e.g., if an ink jet printed article is laundered). Moreover, images applied employing ink jet methodology may also tend to fade or wash out upon prolonged exposure to visible, ultraviolet and/or infrared light. Furthermore, dyes applied to textile substrates may experience severe dye bleed upon application to the substrate. Finally, the color intensity of the image printed on a textile substrate using ink-jet methodology is often lacking in vibrancy.
The nature of textile substrates also pose specific problems when printing or imaging via ink jet print methods, which are not found with common ink jet substrates (e.g. paper or coated paper). For instance, textile substrates are often composed of woven or nonwoven materials. If the textile substrates are composed of nonwoven materials, they can be made from spunbond or meltblown polymeric materials, for example.
As used herein the term xe2x80x9cmeltblownxe2x80x9d means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular die capillaries as molten threads or filaments into converging high velocity gas (e.g. air) streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed meltblown fibers. Such a process is disclosed, in various patents and publications, including NRL Report 4364, xe2x80x9cManufacture of Super-Fine Organic Fibersxe2x80x9d by B. A. Wendt, E. L. Boone and D. D. Fluharty; NRL Report 5265, xe2x80x9cAn Improved Device For The Formation of Super-Fine Thermoplastic Fibersxe2x80x9d by K. D. Lawrence, R. T. Lukas, J. A. Young; and U.S. Pat. No. 3,849,241, issued Nov. 19, 1974, to Butin, et al.
As used herein the term xe2x80x9cspunbondxe2x80x9d refers to small diameter fibers which are formed by extruding molten thermoplastic material as filaments from a plurality of fine, usually circular capillaries of a spinneret with the diameter of the extruded filaments being rapidly reduced as by for example in U.S. Pat. No. 4,340,563 to Appel et al., and U.S. Pat. No. 3,692,618 to Dorschner et al., U.S. Pat. No. 3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992 and 3,341,394 to Kinney, U.S. Pat. No. 3,542,615 to Dobo et al.
Furthermore, other nonwoven processes such as, for example, hydroentangling, air-laid and bonded-carded web processes, may be used to manufacture nonwoven materials for use in textile fabrics. Such materials would normally be hydrophobic in nature, and therefore pose adherence challenges for aqueous based inks. Aqueous inks would tend to wet these materials poorly, thus leading to wicking, bleeding and other problematic print defects.
If the textile substrates are composed of woven materials, the woven or knit threads or strands are formed of fibers. The textile fibers can vary widely in composition, with each composition presenting a unique set of conditions for acceptable printing of the substrate. For example, substrates made of cotton fibers may be very absorbent, such as in the case of aqueous-based inks. When ink is ejected from the ink channel of an ink jet printing device, it is rapidly absorbed into the fibers of the cotton substrate. Since these fibers are much larger that the fibers typically found in paper substrates, the color density or appearance of color brightness is significantly diminished due to the lack of retention of the colorant at the surface of the fibers. In addition, bleeding, mottle of the print pattern, and loss of image sharpness or clarity can often result from printing on the woven textile fabric itself.
Conversely, woven synthetic fibers such as polyester or nylon may be poorly wet by aqueous inks, and such inks may be only retained in the interstitial spaces between the fibers. This limited ink retention also causes the print-quality related problems outlined above.
Furthermore, the permanence of the printed image on textile fabrics is often achieved commercially by some post-printing curing process such as heating, steaming, or chemical fixation. These processes tend to be inefficient, requiring further washing and drying steps to remove unfixed colorant from the fabric. It is therefore desirable to enhance the permanence of the printed image on ink jet printable substrates, and in particular textile substrates, either in the presence or absence of a post-printing curing process step.
Polymeric materials are typically used commercially to modify the properties of both natural and synthetic textile fibers and substrates. These treatments may alter textile appearance or hand, reduce shrinking, reduce flammability, or alter other properties of the fiber or substrate. Treatments may even be employed to enhance the ease of printing and/or print performance when commercial printing processes, such as rotary screen printing, are employed. For instance, polyethylene oxide has been used to pretreat a starting cloth material so as to create an adequate textile substrate for ink-jet printing. As disclosed in U.S. Pat. No. 5,781,216 to Haruta et al., the use of polyethylene oxide treated textile substrates are described as being highly capable of providing images of great color depth with sufficient brightness and sharpness, but free of objectionable color bleed. While Haruta discloses such a polyethylene oxide pretreatment with a cationizing agent, to thereby enhance the coloring ability of images, Haruta requires such treatment to thereafter be cured by additional heating, washing and drying steps.
Use of cationic polymers as part of a latex saturant in a hydroentangled fibrous web is disclosed in PCT US 98 12712 to Harris et al., which was published as WO99/00541 on Jan. 7, 1999. As described in WO99/00541, latex saturation is typically followed by a drying step or other curing aids.
The construction or fabrication of ink jet printable substrates, and in particular, ink jet printable textile substrates which allow for colorfastness and washfastness of ink jet inks without the need for an additional curing or post-treatment step, and which can be easily used in commonly available ink jet or laser printing devices, has proven elusive. Furthermore, feed or holding mechanisms for such ink jet printer devices require a rigid substrate which may be advanced under or across the printing head or drum. Most textile substrates lack the dimensional stability to feed, advance, or otherwise function adequately through such mechanisms and often end up contacting or interfering with the printer heads or drums.
Accordingly, there is still a need in the art for coating formulations and ink jet printable substrate treatment methods which provide for high optical density with a minimum amount of bleeding on the substrate during and after imaging from ink jet printers. There is also a need in the art for such ink jet printable substrate treatment methods which can be applied to textile fabric substrates. In this regard, there is still a need in the art for methods for treating textile fabrics for receiving ink-jet ink formulations, which methods allow for improved colorfastness and color intensity in a wide variety of textile substrates. Furthermore, there is still a need in the art for such substrates which are not dependent upon an ink curing step for construction. Finally, there is also a need in the art for such a textile substrate which includes a backing that can be easily coursed through an ink jet printer and which releases easily from the backing.
The needs described above are addressed by the present invention, which provides a method to modify the adhesion properties and/or colorfastness of ink jet ink formulations when applied to a variety of ink jet printable substrates, by treating the substrates with coating formulations. In particular, a wide array of textile fabric substrates can be treated to improve the colorfastness and washfastness of ink jet ink formulations. The aqueous treatment formulations include between about 5-95% cationic polymers or copolymers, and between about 5-20% fabric softeners. Additionally, the formulations may also include between about 0-80% of a polymeric latex binder so as to increase washfastness. These percentages are based on a conventional measurement for solids content, that is the weight of the dissolved or dispersed solids divided by the total weight of the formulation. Total solids content for the formulations typically range from about 10-50%, but preferably range from about 12-25%. The present methods provides a pathway to fixation of dyes, irrespective of chemical ink class or textile fabric substrate, and without the need of any further ink curing process, by conventional drying under ambient conditions. In addition, efficacy of post printing processes such as steaming or curing may be enhanced by such formulations, reducing dye waste and further enhancing color vibrancy. Also, fixation of pigment or colorant may be enhanced by these formulations.
Additionally, a backing may be applied to such treated textile substrates which enables the substrates to be readily coursed through ink jet printers and still be easily removed for further use, sampling and/or experimentation.
These and other features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiments and the appended claims.